Method for the removal of penetrant

Abstract

An improvement in the method of inspecting a test piece for surface flaws in which an oily based dyed penetrant is applied to the test piece and subsequently the test piece is treated with an emulsifying agent to remove excess penetrant from its surface. The improvement is concerned primarily with using an aqueous soap solution as the emulsifying agent, the soap being a water soluble compound of a fatty acid containing from 12 to 20 carbon atoms. The emulsified penetrant is removed by rinsing with an aqueous solution, the emulsified penetrant, residual soap and rinse water are collected and then the collected liquid is reacted with an aqueous solution of a water soluble calcium or magnesium salt to thereby form a readily filterable curd containing the oily penetrant and a substantially dye-free supernatant liquid layer which can be totally separated from each other.

I claim as my invention: 
     
       1. In the method of inspecting a test piece for surface flaws in which an oily based dyed penetrant is applied to the test piece and subsequently said test piece is treated with an emulsifying agent to remove excess penetrant from its surface, the improvement whereby said excess penetrant is rendered innocuous, said improvement comprising employing an aqueous soap solution as said emulsifying agent, the soap being a water soluble compound of a fatty acid containing from 12 to 20 carbon atoms, removing the emulsified penetrant by rinsing with an aqueous solution, collecting the emulsified penetrant, residual soap and rinse water, and treating the collected liquid with an aqueous solution of a water soluble calcium or magnesium salt to thereby form a readily filterable curd containing said oily based dyed penetrant and a substantially dye-free liquid layer. 
     
     
       2. The method of claim 1 in which said soap is a sodium salt of said fatty acid. 
     
     
       3. The method of claim 1 in which said soap is an amine salt of said fatty acid. 
     
     
       4. The method of claim 1 in which said aqueous soap solution includes a sequestering agent. 
     
     
       5. The method of claim 1 in which said water soluble salt is calcium acetate. 
     
     
       6. The method of claim 1 in which said test piece is immersed in a bath of said emulsifying agent. 
     
     
       7. The method of claim 1 in which said emulsifying agent is sprayed onto the surface of said test piece. 
     
     
       8. The method of claim 1 in which said aqueous soap solution contains butyl carbitol as a gel preventing agent. 
     
     
       9. The method of claim 8 in which said calcium acetate is added in an amount of from 2/3 to 11/2 equivalents per equivalent weight of soap.